Originally Posted by 4given
I just purchased a 1999 540i with 105k and its an automatic.
1. What oil should I use if I'm not sure whats been used previously? Dino or synthetic. Is dino oil ok? I had a Volvo 850 turbo that had 300k until I sold it using dino oil the whole time.
2. Is valvoline ATF-4 synthetic good for the Trans fluid change?
3. When should I change the Diff oil?
4. Anything I can do to beef up the Auto transmission?
P.S. I searched so don't give me a hard time or I'll give you a Cyber Punch to the grill! XD
1. High quality Dino is good. Full synthetic better.
Change Dino after 3K miles. Synthetic 5-7K miles. I have used synthetic for 30 years because of its superior flow during starting (where most of an engine's wear takes place).
2. For your 5 speed trans 83 22 9 407 807 - ZF Lifeguard Fluid 5
You can also take BMW part # - 83 22 9 407 807 and cross reference to another fluid manufacturers like Pentosin.
I have 545i so I use 6-speed trans fluid.
3. Recommend rear diff fluid every 50-60K miles. If you don't know car's history change it now.
4. Beef up transmission ??? Nothing other than fluid and filter change.